A new stem cell study, published in the journal Nature, builds on the potential for this therapy in Parkinson's, but it's still early days and much work remains to be done. A team of researchers demonstrated that human induced pluripotent stem cells (iPSCs) -- "man-made" stem cells created by reprogramming mature adult cells -- are safe and efficacious in a Parkinson's disease (PD) pre-clinical model. (Learn more about stem cells and Parkinson's.)
Scientists engineered dopamine-producing brain cells from iPSCs of people both with and without PD, and then implanted them into the brains of PD pre-clinical models. The grafted cells were safe and functional, and movement improved.
"This work is an important piece in the puzzle for where Parkinson's is and where it's headed," says Brian Fiske, PhD, senior vice president of research programs at The Michael J. Fox Foundation. "These proof-of-concept approaches may have symptomatic benefits for people with PD, but more testing is needed."
Potential Symptomatic Therapy
Stem cells are an important avenue to pursue for the treatment of Parkinson's motor symptoms. But even if we are able to replace the lost dopamine cells, it may not address non-motor symptoms (which often are due to non-dopamine brain chemical problems) or be a cure (because the underlying disease is still present). Still, it would represent a significant advance and another therapeutic route.
"Pursuing varied approaches for Parkinson's can speed more treatment options," says Dr. Fiske. "Stem cell therapy is one route we're following to potentially meet patients' unmet needs."
In 2004, MJFF funded the pre-clinical embryonic stem cell study of Jun Takahashi, MD, PhD, one of the researchers involved in this publication. The current study -- using iPSCs -- is the natural evolution of that work.
The Foundation also is backing other efforts to examine stem cell safety and efficacy in pre-clinical models.
Insight into Disease Process
Stem cells aren't just a possible therapy, they're a research tool, as well. Dopamine cells from iPSCs can mimic the Parkinson's disease process in experiments. Scientists can use this resource to, for example, investigate the impact of genetic mutations and environmental factors, or the effects of drug compounds. To further these efforts, the MJFF-sponsored Parkinson's Progression Markers Initiative (PPMI), an observational study of people with and without PD, is making iPSCs available to the researcher community.
Not a Proven Therapy
We're a step closer, but we still have a ways to go to prove the safety and efficacy of stem cells in people with Parkinson's.
Currently, there are no approved or accepted stem cell treatments for Parkinson's disease, and so, The Michael J. Fox Foundation urges people with PD to view so-called clinics offering stem cell therapies for PD with 'buyer beware' skepticism. At the same time, we are optimistic about the role of stem cells in Parkinson's research, and their potential role in Parkinson's treatment, especially around dopamine replacement. We are actively monitoring the field for progress and potential challenges where MJFF action can support the field.